Unlike in NMT, our intended outputs for a given input are diverse in meaning: we wish to generate multiple semantically distinct possible causes or effects. We induce diversity through hard lexical requirements during decoding, using causal keywords from our CEG as positive constraints on the output. A positive constraint forces the decoder to produce a sequence of tokens that contain the constrained sequence, which is achieved through a constrained beam search proposed by [1]} post2018fast and made efficient by [2]} hu2019improved.
